When it is necessary for a rescue person such as a fire-fighter to work in an environment or atmosphere containing a toxic gas, he usually wears a self-contained breathing apparatus or system. The system usually incorporates a pressurized air supply tank which is carried on the back of the fire-fighter. A flexible air line extends from the tank to a pressure regulator which supplies air at a preselected pressure to a demand inhalation valve, and the inhalation valve has an outlet connected by a flexible breather tube to a face mask worn by the fire-fighter. The inhalation valve is responsive to the air demand within the face mask and is referably constructed to minimize the breathing effort of the fire-fighter.
Occasionally, it is necessary for one fire-fighter using a breathing system to supply emergency air to another fire-fighter who is in distress, for example, by inadvertently depleting his air supply tank or by being trapped within the toxic environment. If the rescue fire-fighter carries with him a transparent plastic hood and an air supply tube, the tube may be used to connect the hood temporarily to the breathing apparatus of the rescue fire-fighter for supplying emergency air to the hood which is placed over the head of the distressed fire-fighter. However, most fire-fighters do not wish to carry with them an emergency air supply hood and another air supply line for the hood.